Steam-engine piston



(No Model.) J. DAVIS.

STEAM ENGINE PISTON.

No. 346,584. atented Aug. 3, 1886.

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UNITED STATES PATENT EEicE.

JOSEPH DAVIS, OF ALTOONA, PENNSYLVANIA.

STEAM 'ENGINE PISTON.

SPECIFICATION forming part of Letters Fatent No. 346,584, dated August3, 1886.

7 Application filed May .26, 1885. Renewed May 25,1886. Serial No.203,261. (No model.)

To all whom it 71mg concern.-

Be it known that I, JOSEPH DAVIS, a citizen of the United States,residing at Altoona, in the county of Blair and State of Pennsyl- Vania,have invented a new and useful Improvement in Steam-Engine Pistons andPackings; and I hereby declare the following to be a full and cleardescription thereof.

The object of this invention is to provide the piston with packing-ringson which the piston rests at the bottom of the cylinder of a horizontalsteam-engine, and which said packingrings automatically adjustthemselves to the upper portions of the cylinder.

Thesiuvention consists in turning eccentric circui'nierential grooves inthe periphery of the piston, and in placing therein respectivelypacking-rings on which the piston shall rest at the bottom of thecylinder, while the eccentricity of the said grooves allows thepackingrings to move laterally, or, rather, radially, at the upperpartof the piston,and thereby adapt themselves automatically to theinterior surface of the cylinder.

The invention will be readily understood by reference to theaccompanying drawings, of which Figure I is a longitudinal sectionalelevation of a horizontal steam-engine provided with one of my improvedpistons and a set of my packing-rings. Fig. II is an elevation of thepiston, showing in dotted lines the eccentric formation of thepacking-ringgrooves. Fig. III is a plan of the portion of thepacking-rings, which represents the mode of overlapping or splicing theends of them.

The piston A is turned up to a true circle, a, circumferentially, whichsaid circle a when the parts are assembled is concentric with theinterior or bore of the cylinder B. The grooves a,which are turnedcircumferentially in the periphery of the piston, are made eccentric toit, as is shown by the dotted line a in Fig. 2, the said bottom line, (0forming the bottom of the said packing'ring groove. The packing-ring Ois made of equal width -all around the piston, and is placed in itsgroove so as to bottom on the groove at the which it is arranged tohabitually impinge by reason of the spring in the metal acting to expandit outwardly for the purpose. The projection of the packing-ring 0beyond the periphery of the piston is habitually uniform on all itssides, as is shown in Fig. 2, and the weight of the piston rests on thebottom of the cylinder through the medium of the interposedpacking-ring,which always keeps the pistonfrom contact with thecylinder, and consequently the piston is never worn; but as the cylinderbecomes worn it can. be rebored and trucd up, and the proper relativepositions of the cylinder and piston be maintained by putting in newpacking-rings. These rings always bottom on the bottom of theirrespective grooves at the lowest part of the piston and automaticallyadjust themselves to the inner surface of the cylinder above that point,by reason of the eccentricity of the said grooves permitting suchautomatic adjustment, and leaving the upperparts of the packing-ringsfree play to move inwardly, the overlapping ends of the packing-ringsserving also to permit the free movement laterally or radially of thepacking-rings for this purpose.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. Inahorizontal steam-engine,apistou provided with circumferentialpacking-grooves eccentric to the piston and receive packingrings onwhich the piston is allowed to rest at the bottom of the cylinder, whilethe cocentricity of the piston-grooves allowsaradial movement andautomatic adjustment of the packing-rings at the top of the cylinder,substantially as shown and described.

2. A steam-engine piston eccentrically grooved circumferentially, and incombination therewith one or more packing -rings,adapted,respectively,to the said grooves, and arranged to support thepiston on the bottom of the cylinder, and to radially and automaticallyadjust themselves to the upper parts of the cylinder, substantially asand for the purpose specified.

In witness whereof I have hereunto set my hand this 19th day of May,1885.

. JOSEPH DAVIS. In presence of- WM. D. OoUcH, THOS. P. FOSTER.

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